Work machines such as, for example, wheel loaders, motor graders, dump trucks, and other types of heavy machinery are used for a variety of tasks. These work machines generally include a power source, which may be, for example, an engine, such as a diesel engine, gasoline engine, or gaseous fuel-powered engine that provides the power required to complete these tasks. To efficiently perform these tasks, the work machines utilize a transmission that is capable of transmitting the torque generated by the engine over a wide range of speeds. The transmission may include, for example, a mechanical transmission, an electric transmission, or a hydraulic transmission. These transmissions may be capable of providing a desired output torque at a desired speed within its operating range by changing a ratio of the transmission.
In some situations such as loading, unloading, uneven loading, or traveling over inconsistent, inclined, or soft or loose terrain, it may be possible for the driven traction devices to slip or spin faster than a traveling speed of the work machine. Slipping can decrease the efficiency of the work machine, increase wear of the traction device, decrease life of the drive train components, and possibly result in unexpected or undesired movement of the work machine.
Traditionally, slip of work machine driven traction devices has been addressed by determining that slip is occurring and then reducing a torque applied to the driven traction device. For example, U.S. Pat. No. 6,799,652 (the '652 patent) issued to Nissen et al. on Oct. 5, 2004 discloses a method of reducing slip of a driving wheel of an industrial truck. The method includes comparing a circumferential measured speed of the wheel to a set point and determining slip. If slip is occurring, the torque applied to a driving motor of the industrial truck is reduced.
Although the method of the '652 patent may minimize wheel slip, it does not prevent the industrial truck from experiencing the disadvantages associated with slipping. In particular, because the method minimizes slipping by measuring wheel slip, some slip must occur before any action is taken to minimize the slipping. By the time wheel slip has been determined and action is initiated, the disadvantages associated with slipping have already been experienced, even if the magnitude of slipping is then reduced.
The present disclosure is directed towards overcoming one or more of the problems as set forth above.